The measurement of objects and use of the measurements to manufacture replacement parts substantially identical to the original objects has long been a goal of industry. In the field of dentistry and the methods of making dental prostheses, e.g., crowns, plates and replacement teeth, this has especially been the case. In the early prior art, the methods required a multiplicity of steps, many of which required intervention in the mouth of the patient. Not only was the patient required to attend the dental practitioner a relatively large number of times, but also the intervention frequently was painful, especially during the fitting stages.
For example, in forming a dental crown, the operations included the grinding of the tooth to be replaced in order to obtain a truncated stamp, the taking of an impression of the stump using an elastomer in order to obtain a mold whose hollow part had a shape that was complementary to that of the stump, the casting of plaster into the mold in order to obtain a reproduction of the stump, the preparation of the crown in wax taking into consideration adjacent and antagonistic teeth (a process that was generally highly subjective and the effect of which required high skill and long years of experience by the practitioner), the positioning of the crown in a coating cylinder, the melting out of the wax, the injection of molten metal to replace the wax, stripping and polishing of the metal crown, and the setting of the crown on the stamp.
In spite of the fact that these numerous operations were carried out by highly skilled dental practitioners, in many cases the prosthesis was then required to be further modified after the initial formation. Because of the large number of steps that were involved, and the fact that even with mechanical impressions accurate fits could not be ensured, and because the relationship of each prosthesis to the adjacent and antagonistic teeth had to be gauged subjectively by the practitioner, the production of a dental prosthesis rarely could be accomplished without many visits to the practitioner for further modifications. Moreover, despite the numerous fitting visits and modifications, the danger that the finished prosthesis would cause discomfort to the patient remained.
Other disadvantages of the early dental prosthesis methods included the use of metals as the material for many dental prostheses. For example, the metals used had to be fluid or malleable at easily obtainable temperatures. The numerous steps required the intervention of a laboratory and skilled practitioners at different stages in addition to a dental surgeon. The equipment, including an oven, sand-blasting machine, and inserting equipment, contributed significantly to the cost of producing the prosthesis.
Because of these many disadvantages, improvements in the prior art were sought to overcome these disadvantages. In certain prior art methods, computer aided design principles were employed to attempt to overcome the drawbacks of the prior art See, for example, Duret et al., U.S. Pat. No. 4,663,720 and Duret, U.S. Pat. No. 5,092,022.
Other advances in the state of the art have included improvements regarding the optical characteristics and color of the teeth. See, for example, Jung et al., U.S. Pat. No. 5,880,826 and Breton et al., U.S. Pat. No. 6,008,905. However, despite the advances of the prior art there still exists a need in the art for method and systems that would allow for further management of information related to the appearance of an object such as teeth.
For example, the system described in Breton et al., U.S. Pat. No. 6,008,905 relies on a CCD-based video camera for imaging the patient's tooth. The image is then signalled to the controller, which is in fact a computer system responsible for digitizing, processing and storing the image data. Although this system has been suitable in the past, it suffered from the problem of insufficient storage. Because the signal produced by the camera was not suitable for direct storage on digital medium, it was required to first process the signal. Thus, it would represent a significant advance in the state of the art if an MAT system were to be developed that was not required to employ a video-based camera for imaging the patient's tooth.